I'm running linux mint 14 mate desktop 64bit after firstly installing cinnamon.Cinnamon was my first choice and I like the multiple desktop concept. However, as I have discovered, and read here on the forum, Linux Mint is very picky about hardware. The install of cinnamon went smoothly. But, the cinnamon desktop used 25% of cpu resource. I have an amd fx8350 with 8 cores. Thats a lot of cpu power. Running a game like Alien Arena caused the cpu to overheat and the cooler to run like a jet engine just to keep it a fraction below 60 celsius. Even firefox browser would do that. Any programs running caused severe demand on all cores. Running system monitor showed that all cores were behaving exactly the same. What I mean is that there was never a time where a single core worked alone. All cores worked at 100% or close to it. After a couple days trying to work out what was wrong, and nearly frying my cpu I might add, well I installed mint 14 again but this time with the mate desktop. At idle, 2 cores sit around 2-4% while the other 6 were 0%. Playing Alien Arena gets a maximum of 4 cores up to 25% at most, but usually much less. And the cores behaved individually as they should do. The fan is quiet, and cpu temp is usually less than 20 celsius, although can go to 30+ celsius with blender rendering cycles. Having firstly installed cinnamon, and the effect it had on this processor, I lost trust in mint despite having a successful install of the mate desktop version of mint 14. So I tried a few other linux versions (ubuntu, arch, zorin) and none had the ease of use that mint has. So I fresh installed mint 14 cinnamon again. Yes, it cooked my processor once again. Fan screaming and cpu temp way too high. So cinnamon was dumped immediately and mate installed and everything has been going well since.

Strange how different desktop versions on the same linux version can have such a severe impact on hardware performance.My system is a new build amd fx8350 on a gigabyte 990fxa-ud3 motherboard with 16GB GSkill ram and sapphire hd7750 graphics card. 240 GB SSD, 2TB Seagate HDD and 640GB Western Digital HDD. Mint is installed on the SSD and boots from the SSD. Bios has not been tweaked although I had to upgrade the bios to the latest version to support the cpu.

I write this so that anyone with similar experience can learn that changing the desktop version might be a solution, as it worked for me.

This is all well known and often discussed here. Cinnamon is built on Gnome3, which is very graphics intensive. You don't say if you tried the proprietary AMD drivers under Cinnamon and/or if the proprietary driver's were able to make better use of the GPU's hardware. This would be the first thing I'd test before ditching Cinnamon.

That said, I'm seriously considering ditching Cinnamon in favour of KDE, which seems to be much better behaved towards my high-end i7. Even with AMD's drivers and two HD5850's in crossfire, Cinnamon is still chewing 15% of CPU0, 7% of CPU1 and 3% of CPU2. And that's when the machine is sitting there doing nothing but twiddling its thumbs. The situation is far worse for laptop owners.

Strange, I have Mint 14 Cinnamon installed on an AMD E450 (a tad better than Atoms, so a very weak processor) laptop and it uses around 6-8% on both CPU cores when idle. MATE uses 1 or 2% less. On the other laptop with an i5-3210m and HD4000 graphics, it fluctuates between 0-4% on each core.

The proprietary AMD catalyst driver should fix the problem. Best might be to install it via command line (usually you get a newer version, depending on which repository you use) or from the MATE proprietary drivers option. It would then work under Cinnamon, too.

Are you sure however, that when you work with Cinnamon, that you are in Cinnamon 3D and not in Cinnamon 2D? Cinnamon 2D would let the CPU do all the graphical work while the GPU just get's bored. Try to make sure at the log-in screen.